1) Field of the Invention
This invention relates a method for generating a short-pulsed microwave and an equipment for generating a short-pulsed microwave, more particular a method for generating a short-pulsed microwave and an equipment for generating a short-pulsed microwave preferably usable in a microwave-related field such as a high frequency-accelerator and a high frequency-radar.
2) Description of the Prior Art
Recently, in a microwave-related field such as a high frequency accelerator and a high frequency-radar, a microwave is required to be short-pulsed in view of high output power.
In the past, the short-pulsing was carried out through directly short-pulsing a voltage to apply a microwave-oscillation tube and an electron beam to oscillate a microwave.
In the case of short-pulsing the voltage to apply the microwave oscillation tube as above-mentioned, however, a high voltage output-circuit is required to be make low-inductance. Moreover, in the case of short-pulsing the electron beam, an output power from an electron beam-generating power supply is required to be short-pulsed. Thus, as a matter of fact, it is difficult to obtain a short-pulsed microwave having a pulse of not more than around 10 nsec.
It is an object of the present invention to provide a new method for generating a short-pulsed microwave and a new equipment for generating a short-pulsed microwave which are able to obtain a microwave having a short pulse extremely easily.
This invention relates to a method for generating a short-pulsed microwave comprising the steps of:charging
charging a given gas into a waveguided tube,
propagating a continuous or a long-pulsed microwave in the waveguided tube, and
making plasma the given gas partially by irradiating a laser to the tube in its cross sectional direction and thereby, dividing the continuous or the long-pulsed microwave with the plasma-part of the given gas to obtain a short-pulsed microwave.
This invention relates to a short-pulsed microwave-generating equipment comprising a microwave oscillator to oscillate a continuous or a long-pulsed microwave, a waveguided tube to propagate the continuous or the long-pulsed microwave and a laser source to generate and oscillate a laser to make plasma a given gas charged into the waveguided tube.
The inventors have been intensely studied to find out a new generating method of a short-pulsed microwave, which replaces the conventional generating methods of a short-pulsed microwave. Based on the novel view of generating a continuous or a long-pulsed microwave and thereafter, dividing the microwave to obtain a short-pulsed microwave, not generating a short-pulsed microwave directly according to the conventional method, they tried to short-pulse a microwave.
Accordingly, the inventors have researched and developed a method to divide the continuous or the long-pulsed microwave. As a result, they have found out that by charging a given gas in a waveguide tube to propagate a microwave and making the gas plasma through irradiation of a laser to the waveguide tube from its outside, the continuous or the long-pulsed microwave can be divided.
That is, when the gas charged in the waveguided tube is made plasma, the microwave can not travel beyond the plasma-part of the gas and reflects at the plasma-part. Thus, the continuous or the long pulsed microwave is divided.
According to the present invention, only by controlling the number of the irradiation point of a laser to the waveguided tube and thereby, varying the number of the plasma-part generated in the waveguided tube, the division number of the microwave can be freely changed. Consequently, a microwave having a desired pulse can be obtained easily and freely.
Herein, the wording xe2x80x9ccontinuous microwavexe2x80x9d means, so-called, a microwave as a continuous wave which has not-pulsed intensity modulation and is oscillated continuously, and the wording xe2x80x9clong pulsed microwavexe2x80x9d means a pulsed microwave having a pulse width of around 1000 nsec.